This invention relates to the field of spray dispensers of the squeeze bottle type. More particularly, it relates to an improved spray dispenser of the squeeze bottle type for use in dispensing nasal sprays, which is of simple construction and which provides means for preventing return of air throug the dispensing orifice.
Spray dispensers of the squeeze bottle type are widely used to administer to the nasal passages liquids containing an anti-cholinergic or decongestant for the relief of sinus congestion or acute or allergic rhinitis caused by conditions such as hay fever, allergies or the common cold. Such spray dispeners should be so designed as to meet certain use criteria, but these criteria are not entirely met by dispensers now in current commercial use.
Thus the dose regimen for each dispenser must be carefully controlled, because if a vasoconstrictor, normally present in nasal decongestant sprays, is over-administered, the resulting excessive vasoconstriction leads to rebound vasodilation of the blood vessels when the effect of the vasoconstrictor wears off. This in turn can produce an intensified congestion, called "rebound congestion", which can tend to perpetuate the rhinitis condition. This problem can be addressed, of course, by controlling the volume of the dosing mechanism, so as to thereby control the per dose medication, and by controlling the total volume of the dispensing container, within the limits allowed by the operating mechanism of the dispenser, so as to control the total available medication. A total dosing regimen for a single dispenser should ideally be sufficient for about seven days, the typical duration of the common cold.
Dispensers of this type should also be provided with a return air passage different from, and relatively remote from, the spray passage so as to prevent, or at least to minimize, inspiration of air through the exit passage during the recovery portion of a use cycle which would otherwise cause contamination of the dispenser contents.
In order to provide effective coverage of the mucous membranes, the dispenser should also be so designed that air and the liquid medication in the dispenser are well-mixed in the dispensing head in order that the material be dispensed as a fine spray rather than as a liquid steam or large droplets.
Finally, because of the shape of the nasal fossae, i.e. the cavities on either side of the midline of the face and lying directly behind the nares or nasal openings, the spray pattern delivered by the dispenser should advantageously be relatively oval, or elliptically, shaped, rather than circular as in conventional spray dispensers, in order to better insure reaching all surfaces of the fossae, which are generally triangular in cross sectional shape, tapering from about 15 mm. wide at the bottom to about 1 mm. wide at the top.
As will be seen, the dispensers provided by the present invention overcome these problems and meet the basic criteria for nasal spray dispensers, as described above, by use of a relatively simple dispensing head section, which consists of only three basic parts, in combination with a conventional squeeze bottle.